Astronomers have uncovered further evidence that planets like Jupiter act as meteor magnets–shielding us from space objects that would otherwise slam into Earth. Questioning if giant planets act as guardians of solar systems elsewhere in the galaxy.
A team of astronomers have discovered two Jupiter-sized planets–150 light years away from Eart–that could reveal whether life is likely on the smaller planets in other solar systems thanks to the intervention of giant planets acting as meteor magnets.
Stephen Kane, lead study author and UCR associate professor of planetary astrophysics, explains the importance of gas giants acting as meteor magnets: “We believe planets like Jupiter have profoundly impacted the progression of life on Earth. Without them, humans might not be here to have this conversation.
“Understanding how many other stars have planets like Jupiter could be very important for learning about the habitability of planets in those systems.”
Along with liquid water oceans, Kane and other astronomers believe such planets have the ability to act as ‘slingshots’– pulling objects like meteors, comets, and asteroids out of their trajectories diverting them from impacting with small, rocky planets.
Locating meteor magnets with a novel technique
Many larger planets have been found close to their stars. However, those aren’t as useful for learning about the architecture of our own solar system, where the giant planets including Saturn, Uranus and Neptune are all farther from the sun. Big planets far from their stars have, until now, been harder to find.
Kane’s team found used a novel approach combining traditional detection methods with the latest technologies. A study detailing their findings have been accepted for publication in the Astronomical Journal.
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One of the primary methods of searching for exoplanets in other solar systems involves monitoring stars the “wobble” produced in the primary star’s orbit caused by the gravitational effects of planets in orbit around it. Thus when a star wobbles, it’s a clue there may be an exoplanet nearby.
When the planet is far from its star, the gravitational pull it exerts is weaker, thus making the wobble smaller and harder to detect. Another problem with using the wobble detection method, Kane points out, is that it just takes a long time.
Consider an example from our solar system; Earth may only take a year to orbit the sun, but Jupiter takes 12, Saturn takes 30, and Neptune takes an astonishing 164 years! Larger exoplanets also take many years to circle their stars, meaning observing a complete orbit could take an astronomer’s entire career.
To accelerate the process for the less patient astronomer, Kane and his team combined the wobble method with direct imaging. This way, if the team thought a planet might be causing wobble, they could confirm it by sight.
Obtaining a direct image of a planet quadrillions of miles away is no simple task. It requires the largest possible telescope, one that is at least 32 feet long and highly sensitive. Even from this distance, the light of the stars can overexpose the image, obscuring the target planets.
The team overcame this challenge by learning to recognize and eliminate the patterns in their images created by starlight. Removing the starlight allowed Kane’s team to see what remained.
Kane adds: “Direct imaging has come a long way both in terms of understanding the patterns we find, and in terms of the instruments used to create the images, which are much higher resolution than they’ve ever been.
“You see this every time a new smartphone is released – the camera detectors are always being improved and that’s true in astronomy as well.”
In this project, the team applied the combination of wobble and imaging method to 20 stars. In addition to the two being orbited by giant Jupiter-like planets that had not been previously discovered, the team also detected a third, previously observed star with a giant planet in its system.
Going forward, the team will continue to monitor 10 of the stars where planetary companions could not be ruled out. In addition, Kane is planning a new project to measure how long it takes these exoplanets to complete rotations toward and away from their stars, which cannot currently be measured.
Kane concludes: “This discovery is an important piece of the puzzle because it helps us understand the factors that make a planet habitable and whether that’s common or not.
“We are converging rapidly on answers to this question that the past 3,000 recorded years of history could only wish they had available to them.”